342 A NEW MYLODON. 
Until more material from the same locality and formation is available, it does 
not seem best to attempt the definite identification of Cope’s Mylodon sodalis. 
The supposed lack of the bony sheath on one side of Cope’s type specimen seems 
more than likely to be due to a breakage, for in one of the phalanges of our speci- 
men a similar appearance is presented where the thin sheath has broken so 
smoothly away on one side as to suggest that this is its normal condition, but 
the broken piece was found and fitted perfectly. 
CoMPARATIVE Notes ON MyYLODON HARLANI OWEN. 
This species, though known from numerous fragments from many parts 
of the southern United States, has never been adequately described. It was 
based on a portion of the ramus including the lower dentition from Big Bone 
Lick, Kentucky. Cope (1895) subsequently described and figured teeth from 
Louisiana, which were assumed to represent the upper series. In the same paper 
he names two new species, M.renidens and M. sulcidens, which appear to rep- 
resent the same animal, and are currently regarded as synonyms of M. harlani. 
Leidy (1885, 1889) lists a number of bones in the collections of the Academy of 
natural sciences and the Wagner free institute at Philadelphia, including a 
left malar bone, fragments of vertebrae, and of limb bones and pubis. The 
complete skull remains unknown. Prof. T. D. A. Cockerell, however, in 1909 
published a short account, with photographic figures of a Mylodon cranium 
discovered on a farm near Walsenburg, Colorado. This he inclined at first to 
consider the same as Paramylodon nebrascensis but decided it might be in reality 
an undescribed species. Through his kindness I have been able to examine 
carefully the original photographs as well as drawings of the tooth sockets, made 
at my request by Professor Cockerell. The upper teeth were five as typically 
in the genus, and although there are certain resemblances to the skull of Para- 
mylodon, the differences are marked. After a careful comparison with Cope’s 
figures, drawn natural size, of the upper dentition, and allowing for the fact that 
the diameters of the tooth sockets are several millimeters in excess of those 
of their respective teeth, I am impressed by the very close correspondence both 
in form and in measurements between Cope’s figures and Professor Cockerell’s 
photographs and drawings, so that there seems little doubt that the Colorado 
skull should be referred to M. harlani, of which no entire cranium had hitherto 
been discovered. 
In 1843, Harlan described as a new species under the name Orycterotherium 
missouriense the remains of three Mylodons found on the Big Bone River, a 
